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"POLARITY" (SK8) to "INVERT"
"V/cm" (SK4-SK10) to ".Ol V"
"V/cm" (R3-RS) to "CAL."
"DEFLECTION" (SK3-SK9) to "D.C."
The rejection factor must be greater than 100 x , and
can be checked as follows.
Set "MODE" (SKS) to "A" (B) and in both positions
adjust the time-base line to the centre of the screen
with "SHIFT" (Rl) (R7).
Adjust the sensitivity of channel A according to
point "D".
Apply simultaneously identical voltages of 100
mVp_~,, frequency 50 Hz, symmetrical around
earthing level, to channels A and B.
Set "MODE" (SKS) to "ADDED."
By means of "GAIN" (R6), adjust the sensitivity of
channel B so, that the vertical defection is minimum.
The rejection factor exceeds 100 x , if the vertical
deflection does not exceed 1 mm after this adjust-
ment
— Increase the frequency of the input voltage to 1 MHz
and repeat the abovementioned measurement.
M. TRIGGERING
— Set the belowmentioned knobs of the basic oscillos-
cope to the follwing positions:
"TRIGG. MODE" to "H. F."
"TRIGG. SLOPE" to "-~"
"TRIGG. SOURCE" to "INT. ".
"STABILITY" to "PRESET"
— Set "MODE" (SKS) and "TRIGG." (SK6) to posi
tion A.
— Set "V/cm" (R3-RS) to "CAL."
— Apply asine-wave voltage with a frequency of 10
MH to channel A and adjust the trace height to 3
mm.
With "LEVEL" (R2) on the basic-oscilloscope, a
correctly triggered display should be obtained at this
trace height.
Set "TRIGG." (SK6) to "B."
The display should not remain triggered.
Set "MODE" (SKS) and "TRIGG." (SK6) to posi-
tion "B".
Apply the voltage to channel B and check in the same
way the triggering at a trace height of 3 mm.
— With "TRIGG." (SK6) to position "A", the display
should not remain triggered.
— Decrease the frequency of the input voltage to 100
kHz and adjust the trace height to 40 mm.
— Check the trigger polarity on both channels.
With "POLARITY" {SK2 and SK8) to "NORMAL"
time base A should start on the positive-going edge
of the signal.
— Check that in position "ADDED" of "MODE"
(SKS), the trigger voltage is taken off via relay
RE601.
For this, apply a voltage with a frequency of 100
kHz to channel A and with "LEVEL" of the basic
oscilloscope, adjust for a triggered display.
— The triggering should not be affected by switching
over "TRIGG." (SK6).
— With "POLARITY" (SK2 and SK7) to "NORMAL"
time base A should start again on the positive-going
edge of the signal.
N. CHOPPING
1. Frequency
Set "MODE" (SKS) to position "CHOPPED".
In this position, two time-base lines should be written
which can'be shifted with respect to each other with
"SHIFT" (R1 and R7).
With "SHIFT" (R1-R7) adjust the distance between
both time-base lines to approximately 5 cm.
Both time-base lines should be periodically inter-
rupted in the frequency of the switching voltage.
With SK11, at the right hand side of the unit, it
should be possible to adjust the switching frequency
to 20 kHz or 500 kHz.
— Check in both positions of SK11 the switching fre-
quency by measuring the period time. For this, the
basic oscilloscope should be triggered externally by a
signal from terminal 2 of T501 at the dual trace unit
(see Fig. 13). Apply this signal to "EXT." (BU1) of
the basic oscilloscope and set "TRIGG. SOURCE"
(SK3) to "EXT".
— In position 20 kHz of SK11, the period time should
be between 40 and 60 µsec., in position 500 kHz
between 1.6 and 2.4 µsec.
2. Blanking
— Trigger the basic oscilloscope externally with the
switching voltage as indicated in point N1.
Adjust the switching frequency to 500 kHz (SK11)
and check the blanking. The blanking can be
switched on with switch SK14 at the rear of the basic
oscilloscope.
— Without blanking (SK14 to position "EXT."), the
edges of the switching pulses are visible. When SK14
is set to position "MULTI-TRACE-CHOPPER",
the edges should not be visible.
3. Ext. chopped
— Set "MODE" (SKS) to position "EXT. CHOPPED".
— Check that the chopper operates with an external
driving voltage. For this, apply a symmetrical
square-wave voltage with a frequency of 100 kHz
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